As one kind of semiconductor devices, a NAND type flash memory device having a three-dimensional structure is known in the art. In the manufacture of the NAND type flash memory device having the three-dimensional structure, by performing an etching process of etching a multilayered film in which silicon oxide films and silicon nitride films are alternately stacked on top of each other, a deep hole is formed in the multilayered film. This etching process is described in Patent Document 1.
To be specific, in Patent Document 1, there is disclosed a method of etching a multilayered film by exposing a processing target object having a mask on the multilayered film to plasma of a processing gas.
Patent Document 1: US Patent Application Publication No. 2013/0059450
A processing target object to be etched may include a first region including a multilayered film in which first dielectric films and second dielectric films (silicon nitride films) are alternately stacked on top of each other; and a second region including a single-layered silicon oxide film. It is required to form spaces such as a hole and/or a trench both in the first region and in the second region by etching the processing target object. Further, when performing this etching process, it is also required to form the spaces having desirable shapes in the first region and the second region while suppressing a decrease of an etching rate.